Chapter 13A: Work and Mechanical Advantage Chapter 13B: Levers and Torque

Work

The transfer of energy when a force acts on an object to move it over a distance

Power

The rate of doing work

Simple Machines

Basic mechanical devices that change the magnitude, direction, or distance traveled of the force used when doing work

Mechanical Advantage (MA)

The amount by which a simple machine multiplies an input force

Ideal Mechanical Advantage (IMA)

The mechanical advantage for an ideal machine (100% efficient) with no friction

Actual Mechanical Advantage (AMA)

The mechanical advantage that accounts for all real-world mechanical losses and friction

Efficiency

A comparison of the amount of useful energy remaining after a process with the original amount of energy

Lever

A simple machine that consists of a rigid bar that turns about a pivot point (the fulcrum)

Fulcrum

The point about which a lever pivots or rotates

Torque

A force that causes a rotation about a pivot point

Law of Torques

For a system to be in rotational equilibrium (balanced), the sum of the torques on the system must be zero

1st Class Lever

A lever with the fulcrum in the middle

2nd Class Lever

A lever with the load in the middle

3rd Class Lever

A lever with the effort in the middle